Blinding Procedures Both patients and medical staff will be blinded to the treatment arms. Both the nimodipine (30 mg po qid) and placebo groups (placebo po qid) will receive 8 identical tablets with the same instructions for self-administration. The capsules will be only be identified by a unique study number to allow accurate analysis at the end of the study. A single pharmacy will be responsible for blinding, labeling and packaging the medication. Only the study coordinator (DN), who will not be involved clinically with study participants, will remain unblinded.